Fionn76: Curious.................I asked something, and in the post people starting to answer someone who cant make a post on his/her own. Sure if I go to another post and start to ask my question, the post owner tell me to create a post for my question.
Actually, my comment about mouse acceleration, or an .ini file tweak, was in response to your problem. I was trying to answer both of you, but I didn't make it clear which answer was for which question, sorry! I definitely feel like I've heard of this issue before but I can't remember what the fix is. Anyone else know?
Oh another thing you can try is this: right-click on the shortcut to Arcanum that's on your desktop. In the "target" field you'll see something like "c:\blah\blah\arcanum.exe". Add "-no3d" to this field, OUTSIDE the quotes and with a space between, so it reads:
"c:\blah\blah\arcanum.exe" -no3d
Then run the game from that shortcut and see if it fixes your mouse issues.